1. Field of the Invention
The present invention relates to a VoIP wireless telephone system and method utilizing a wireless LAN, wherein expansion of an IP wireless extension telephone is realized in a VoIP service by communicating via the wireless LAN.
2. Description of the Related Art
Recently, IP telephone services through the Internet attract attention because of their inexpensiveness.
For example, there is known a wireless communication system in which a wireless terminal (client) accesses a DNS (Domain Name System) server via a DHCP (Dynamic Host Configuration Protocol) server to get an Internet telephone service (for example, see JP-A-11-55317).
Currently, however, such an IP telephone service has factors inferior to a general telephone service on convenience, for example, no “wireless device” has yet existed. For this reason, improvement of such an IP telephone service, for example, realization of a wireless terminal, is expected.
On the other hand, in the conventional wireless communication system, because assigning an IP address is done by the DHCP server, no user authentication is executed upon connection from each client to the DHCP server. In addition, because all the clients under the DHCP server exist on the same LAN, direct communication between clients is possible. That is, there is no user authentication procedure between each client and the DHCP server and no authentication procedure between clients. Thus, the conventional wireless communication system has no securing means for a leak of information, a malicious attack, and so on. There is weakness on security.